1865968121 has 2 divisors, whose sum is σ = 1865968122. Its totient is φ = 1865968120.

The previous prime is 1865968063. The next prime is 1865968123. The reversal of 1865968121 is 1218695681.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1804125625 + 61842496 = 42475^2 + 7864^2 .

It is a cyclic number.

It is not a de Polignac number, because 1865968121 - 2²² = 1861773817 is a prime.

Together with 1865968123, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1865968123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 932984060 + 932984061.

It is an arithmetic number, because the mean of its divisors is an integer number (932984061).

Almost surely, 2^1865968121 is an apocalyptic number.

It is an amenable number.

1865968121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1865968121 is an equidigital number, since it uses as much as digits as its factorization.

1865968121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 207360, while the sum is 47.

The square root of 1865968121 is about 43196.8531376997. The cubic root of 1865968121 is about 1231.1228913386.

The spelling of 1865968121 in words is "one billion, eight hundred sixty-five million, nine hundred sixty-eight thousand, one hundred twenty-one".